diff --git a/build.rs b/build.rs
index a1c3eae7..7946d81b 100644
--- a/build.rs
+++ b/build.rs
@@ -60,8 +60,9 @@ fn main() {
                     "could not execute `mandoc` or `man`. If the binaries are not available in the PATH, disable `cli-docs` feature to be able to continue compilation.",
                 );
 
-            let file = File::create(&out_dir_path)
-                .expect(&format!("Could not create file {}", out_dir_path.display()));
+            let file = File::create(&out_dir_path).unwrap_or_else(|err| {
+                panic!("Could not create file {}: {}", out_dir_path.display(), err)
+            });
             let mut gz = GzBuilder::new()
                 .comment(output.stdout.len().to_string().into_bytes())
                 .write(file, Compression::default());
diff --git a/src/components/mail/listing.rs b/src/components/mail/listing.rs
index 6e75a44b..72ec4703 100644
--- a/src/components/mail/listing.rs
+++ b/src/components/mail/listing.rs
@@ -84,8 +84,7 @@ impl<T> RowsState<T> {
         self.thread_to_env
             .get(&thread)
             .iter()
-            .map(|v| v.iter())
-            .flatten()
+            .flat_map(|v| v.iter())
             .any(|env_hash| self.selection[env_hash])
     }
 
@@ -169,6 +168,11 @@ impl<T> RowsState<T> {
         self.entries.len()
     }
 
+    #[inline(always)]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     #[inline(always)]
     pub fn clear_selection(&mut self) {
         for (k, v) in self.selection.iter_mut() {
diff --git a/src/components/mail/listing/plain.rs b/src/components/mail/listing/plain.rs
index c54294c3..abcc9717 100644
--- a/src/components/mail/listing/plain.rs
+++ b/src/components/mail/listing/plain.rs
@@ -689,7 +689,7 @@ impl PlainListing {
         let mut subject = e.subject().to_string();
         subject.truncate_at_boundary(150);
         EntryStrings {
-            date: DateString(PlainListing::format_date(&e)),
+            date: DateString(PlainListing::format_date(e)),
             subject: SubjectString(subject),
             flag: FlagString(format!(
                 "{selected}{unseen}{attachments}{whitespace}",
diff --git a/src/types.rs b/src/types.rs
index e50a9797..b338e873 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -94,7 +94,7 @@ pub enum ForkType {
     NewDraft(File, std::process::Child),
 }
 
-#[derive(Debug, PartialEq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
 pub enum NotificationType {
     Info,
     Error(melib::error::ErrorKind),